The present invention pertains to methods and composition for treating waste and effluent waters originating from sources including but not limited to manufacturing as well as excavation and mining operations.
Many times, water effluent is a necessary product of manufacturing and mining operations. The water effluent produced can include one or more trace compounds that are dissolved or suspended in the process stream. Many of these trace compounds that are entrained in the process stream can have deleterious or adverse effects if discharged into the surrounding environment. Discharge of many such compounds is regulated by various state, local and federal environmental agencies.
In operations such as mineral and energy extraction, copious amounts of water can sometimes be employed in various processes and sub processes. Typically, this water must be processed prior to discharge to reduce or eliminate process contaminants. In certain situations, such as mineral extraction operations, the extraction sites themselves, whether active or inactive, provide a generation source as water from rain, storm water runoff and aquifer leaching carries various contaminants away from the original extraction site into the surrounding environment. In mining operations, this is generally referred to as Acid Mine Drainage (AMD) or acid rock drainage. Acid mine drainage results from oxidation of metal sulfide minerals such as pyrites and other ores. The various extraction sites can produce effluent that has elevated levels of one or more of the following metal contaminants, sulfur-containing compounds, volatile and dissolved organics. These contaminants can exist in either dissolved or suspended for and can be present as ions or as compounds such as higher oxidation state compounds.
Metal contaminants and metal compounds can include heavy metals and/or light metals. Heavy metals include, but are not limited to, iron, copper, zinc, magnesium, manganese, aluminum, cadmium, nickel and lead, selenium, mercury, cobalt and the like. Sulphur containing compounds include various sulfates, sulfides, and sulfites. Additionally, the water material can contain various cyanides, cyanates and the like.
Past efforts have been directed to processes that can treat moderate to high concentrations of dissolved metals and sulfates, i.e. levels above about 5000 ppm. In many processes, treatment technology employs a variety of tactics to precipitate metal contaminants and reduce sulfate and cyanate concentration. Unfortunate side effects of such processes include the precipitation of hazardous material as metal hydroxides and calcium sulfate which results in significant disposal costs and necessitates the use of hazardous and/or difficult-to-handle reagents. Additionally, the nature, quality and contaminant panel varies from origination site to origination site, making it difficult to provide remediation process and protocol that is efficient and effective across a variety of locations and situations.
It has been difficult to provide processes that adequately address and remediate the environmental challenges specific to each given generation site. It would be desirable to provide a device and method that can address and mitigate various target compounds at a variety of concentration levels present in the specific effluent material such as material associated with acid mine drainage. It would also be desirable to provide a device and method that can address and mitigate various target compounds at various concentration levels in industrial process streams.